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LibWeb/Infra: Use Utf16View for code_unit_less_than

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The Utf16View implemention is a more effecient implementation
and less code overall.
This commit is contained in:
Shannon Booth 2025-05-15 17:57:11 +12:00 • committed by Tim Flynn
commit d1a40b7951
Notes: github-actions[bot] 2025-05-17 12:02:03 +00:00
1 changed files with 7 additions and 27 deletions
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34
Libraries/LibWeb/Infra/Strings.cpp
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@ -150,35 +150,15 @@ String isomorphic_decode(ReadonlyBytes input)
// https://infra.spec.whatwg.org/#code-unit-less-than
bool code_unit_less_than(StringView a, StringView b)
{
// FIXME: There should be a way to do this without converting to utf16
// FIXME: Perhaps there is a faster way to do this?
// 1. If b is a code unit prefix of a, then return false.
if (is_code_unit_prefix(b, a))
return false;
// Fastpath for ASCII-only strings.
if (a.is_ascii() && b.is_ascii())
return a < b;
// 2. If a is a code unit prefix of b, then return true.
if (is_code_unit_prefix(a, b))
return true;
auto code_units_a = MUST(utf8_to_utf16(a));
auto code_units_b = MUST(utf8_to_utf16(b));
auto view_a = Utf16View(code_units_a);
auto view_b = Utf16View(code_units_b);
// 3. Let n be the smallest index such that the nth code unit of a is different from the nth code unit of b.
// (There has to be such an index, since neither string is a prefix of the other.)
size_t n = 0;
size_t min_length = min(view_a.length_in_code_units(), view_b.length_in_code_units());
while (n < min_length && view_a.code_unit_at(n) == view_b.code_unit_at(n))
++n;
// 4. If the nth code unit of a is less than the nth code unit of b, then return true.
if (view_a.code_unit_at(n) < view_b.code_unit_at(n))
return true;
// 5. Return false.
return false;
auto a_utf16 = MUST(utf8_to_utf16(a));
auto b_utf16 = MUST(utf8_to_utf16(b));
return Utf16View { a_utf16 }.is_code_unit_less_than(Utf16View { b_utf16 });
}
}